振动对FV520B不锈钢MAG堆焊再制造成形组织结构的影响（英文）

Effect of Vibration on Remanufacturing Microstructure of FV520B Stainless Steel Using MAG Surfacing Deposition Technology

采用堆焊熔敷成形技术进行了FV520B沉淀硬化不锈钢再制造实验,在此基础上,对FV520B不锈钢熔化极活性气体保护电弧焊(metal active gas arc welding,MAG)堆焊再制造成形组织特点进行了分析,并研究了机械振动对再制造成形组织的影响。结果显示:FV520B不锈钢MAG堆焊再制造成形组织由马氏体+碳化物沉淀硬化相组成,且沿成形高度方向组织呈周期性变化特点,具有一定的自相似分形特性;振动会一定程度上增大孪晶形成几率,对马氏体板条具有破断作用,且马氏体板条宽度随振动转速的不断增大呈先减小后增加趋势;受振动的影响,晶格畸变和各晶面择优取向性都将发生变化,但不同晶面变化规律不同;振动的加入使得(110)晶面和(211)晶面的Bragg衍射峰峰位向低衍射角方向发生偏移,且随振动转速的不断增大,偏移量呈先增大后减小趋势,(110)晶面衍射峰半高宽呈先减小后增大趋势,其晶面择优取向(TC)性则呈现先增强后减弱趋势;在0到共振转速区间内(211)晶面衍射峰半高宽随振动转速的不断增大呈先减小后增大趋势,当振动转速大于共振转速时又呈减小趋势,但其晶面择优取向(TC)性则随振动转速的增大呈现持续增强趋势;总体上,亚共振频率振动(振动转速f=3000r/min)对FV520B不锈钢MAG堆焊再制造成形组织结构的影响最显著。

The remanufacturing experiment of FV520 B precipitation hardening stainless steel was carried out by metal active gas arc welding(MAG) surfacing deposition technology. On this basis, the characteristics of remanufacturing microstructure were analyzed, and the effect of mechanical vibration on remanufacturing microstructure was studied. The results show that the remanufacturing microstructure of FV520 B stainless steel by MAG surfacing deposition technology is composed of martensite+carbide precipitation-hardening phase. It exhibits a characteristic of periodical variation along the direction of forming height, which is described by certain self-similar fractal characteristics. The vibration increases the probability of twin formation to some extent, which has a broken effect on the martensite lath. The width of the martensite lath decreases first and then increases with the continuous increase of the vibration rotation rate. Affected by the vibration, the lattice distortion and the preferred orientation(TC) of each crystal plane are changed. However, the change rule of different crystal planes is different. The Bragg diffraction peak positions of planes(110) and(211) shift toward the direction of lower diffraction angle due to the addition of vibration. Furthermore, the offset increases first and then decreases with the continuous increase of the vibration speed. Meanwhile, the FWHM of diffraction peak(110) decreases first and then increases while the preferred orientation of this crystal plane increases first and then decreases. Within the range between 0 and the resonance speed, the FWHM of diffraction peak(211) decreases first and then increases with the continuous increase of the vibration speed, and then decreases again when the vibration speed is higher than the resonance speed. However, its TC continues to increase with the increase of the vibration rotation rate. In general, the sub-resonance frequency(the vibration rotational speed f=3000 r/min)has the most significant effect on the remanufacturing microstructure of FV520 B stainless steel using MAG surfacing deposition technology.